JPH09149669A - Method for identifying inertia - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for identifying the inertia in real time through a small quantity of simple operation. SOLUTION: In the method for identifying the inertia of motor 16 speed controller having at least proportional term and integral term, an integral term is subtracted from a torque command obtained in the speed controller and passed through a filter using the speed output of the motor 16 to obtain a value 1, and the speed output of motor is passed through a specific filter and differentiated to obtain a value 2. The value 1 is divided by the value 2 to obtain an inertia identification value including the motor and load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inertia identification method applied to control devices such as robots and machine tools.

[0002]

2. Description of the Related Art As a method for identifying an inertia including a motor and a load, for example, (1) a constant torque is applied to a motor to accelerate or decelerate,
A method of identifying inertia from the acceleration / deceleration time. (2) A method of inputting a torque command to a given model, comparing the speed output of the model with the speed output of the motor, and identifying the inertia so as to minimize the error. and so on.

[0003]

However, the above-mentioned conventional example
In (1), a series of operations for accelerating or decelerating the motor, detecting the acceleration / deceleration time, and identifying the inertia must be performed several times. In (), since identification cannot be performed, there is a problem that it cannot be applied to a control object such as a robot whose load inertia constantly changes. Also, in (2), an error due to modeling error and disturbance generally occurs between the model speed output and the actual speed output, and a predetermined calculation is performed to minimize this error. There is a problem that it is complicated and large. Therefore, it is an object of the present invention to provide an inertia identification method that can be identified in real time and can be realized with a very simple and small amount of calculation.

[0004]

In order to solve the above problems, the present invention provides an inertia identification method for a motor speed controller having at least a proportional term and an integral term, in the speed controller. The value obtained by subtracting the integral term from the torque command obtained by the above and the speed output of the motor are used to obtain a value obtained by passing a predetermined filter to the value obtained by subtracting the integral term from the torque command and the speed output of the motor. A value obtained by differentiating a value passed through a predetermined filter is calculated, and the value obtained by dividing the value by the value is used as an inertia identification value including the motor and the load.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below. FIG. 1 is a block diagram of a motor control system to which the present invention is applied. Here, a speed command is input, and a speed loop is set to PI (proportional integral) so that the speed of the motor matches the speed command. It shall consist of controls. Reference numeral 11 in the drawing is a subtracter, which subtracts the motor speed from the input speed command to create a speed deviation. 12 is a velocity loop gain Kv, 13 is an integrator with a time constant Ti, 14 is an adder, 15
Is a torque control device. Further, 16 is a motor, 17 is a load inertia, and 18 is a speed detector. And 1
Reference numeral 9 is an inertia identifier to which only the proportional term of the torque command and the speed output from the speed detector 18 are input.

Next, the calculation in the inertia identifier 19 will be described with reference to FIG. The proportional term of the input torque command (12 output of FIG. 1) is passed through the primary filter 21a having a time constant Tk1 in the figure 21 (hereinafter, this signal is referred to as). Similarly, the inputted velocity is differentiated by the differentiator 22 after passing through the primary filter 21b having the time constant Tk2 (hereinafter, this signal is referred to as). Then, the operator identification value J including the motor and the load is calculated as J =
It is calculated from the division of /. Instead of, the following may be used instead of, and J = / may be used. = A value obtained by integrating a value obtained by subtracting an integral term from a torque command obtained in the speed control device or a value of the integral term, and a mode
Value obtained by subtracting an integral term from the torque command by using a speed output of the motor and passing a predetermined filter = value obtained by passing a predetermined filter on the speed output of the motor

If the inertia is obtained in this way, the optimum values of the control parameters (speed loop gain Kv, time constant Ti) can be obtained by a known method.

[0008]

As described above, according to the present invention, since the inertia identification including the motor and the load can be realized by a very simple and small amount of calculation and can be performed in real time, the robot etc. It can also be applied to a controlled object whose load inertia constantly changes.

[Brief description of the drawings]

FIG. 1 is a block diagram of a motor control system to which the present invention is applied.

FIG. 2 is a block diagram of the inertia identifier 18.

[Explanation of symbols]

 11 Subtractor 12 Speed Loop Gain Kv 13 Integrator of Time Constant Ti 14 Adder 15 Torque Control Device 16 Motor 17 Load Inertia 18 Speed Detector 19 Inertia Identifier 21a Primary Filter of Time Constant Tk1 21b Primary filter with time constant Tk2 22 Differentiator 23 Operator

Claims (2)

[Claims] 1. A method for inertia identification of a motor speed controller having at least a proportional term and an integral term, comprising: a value obtained by subtracting the integral term from a torque command obtained in the speed controller; Using the speed output of the above, a value obtained by differentiating the value obtained by subtracting the integral term from the torque command with a predetermined filter and the value obtained by passing the predetermined output with the speed output of the motor are calculated. A method for inertia identification, wherein a value obtained by dividing the value by the above value is used as an inertia identification value including a motor and a load. 2. An inertia identifying method for a motor speed controller having at least a proportional term and an integral term, wherein a value obtained by integrating a value obtained by subtracting the integral term from a torque command obtained in the speed controller is used. , A value obtained by integrating a value obtained by subtracting an integral term from the torque command or a value obtained by passing a predetermined filter to the value of the integral term and a predetermined value for the velocity output of the motor using the speed output of the motor. An inertia identification method, which comprises calculating a value that has passed through a filter, and dividing the value by the value to obtain an inertia identification value including a motor and a load.